I keep seeing the same question continually in the road cycling, touring and commuting fora, with similar posts under general discussion. It is: I am buying a bike what should I do? At the moment there are two threads on this topic in road cycling separated by no more than two other posts. The guidance always includes the following:
Fit is paramount
the best place to get a good fit is the LBS
the most important measure in fit is top tube length
there are links to good fit pages
the second issue is frame material
we have dozens of steel vs al posts, the essence of which is: steel may ride better, but unless you get the stiffest of bikes, you will get a good ride from al too
and for tourists, steel may be easier to get fixed in odd places
The third issue is drive train, and there is not much said that isn't on sheldon brown's pages
The fourth issue is wheels, and here is the only place I have not been able to see a clear consensus on anything much, other than it makes a lot more sense for recreational cyclists to pay attention to durability than to minor differences in weight
the fifth issue is tires, and other than how hard they are to get on, and how easily they get flats, there is no emerging consensus.
Seeing that, we should have FAQ's on the first three issues.